The Brain and Crime

Guy Sutton The brain and crime Are criminals ‘born or made’? Does brain Brain anatomy and function Key words damage result in criminal behaviour or do some The brain controls all thoughts and actions. The two brain individuals have a genetic predisposition to crime? cerebral hemispheres are divided into four lobes. crime Or is criminality more likely to be influenced by The frontal lobes, comprising around one third of brain damage social factors? Recent research suggests that the the brain’s hemispheres, are involved in mental and genetics social world influences the activity of our genes, in behaviour functions such as thinking, personality and control of emotional expression. turn affecting brain function. Neuroscientists are • The temporal lobes are involved in memory, now beginning to explore how the brain might be together with hearing, smell, and recognising linked to certain criminal behaviours. objects and faces. • The parietal lobes integrate sensory information. • The occipital lobe is responsible for vision. Beneath the surface of the brain, complex brain regions exist such as the limbic system. This includes the two amygdalae; one in each parietal lobe hemisphere and involved in emotion, memory, frontal lobe aggression and fear. The hippocampus curves back from the amygdala in each hemisphere and is involved in emotion and memory. temporal lobe occipital The damaged brain and altered lobe behaviour Brain damage could potentially influence behaviour in many ways, for example, by impairing learning or judgement. There is a growing amount of evidence brain stem cerebellum linking brain injury to criminality. Compared with the general population, there is a higher rate of brain damage amongst offenders in custody. The major regions of the human brain Brain damage in childhood and early adulthood may increase the likelihood of criminal behaviour. 6 Catalyst February 2016 www.catalyststudent.org.uk Phineas Gage Donta Page In 1848, Phineas Gage, a US construction In Denver, USA, Donta Page was convicted of foreman, was involved in a work-related the brutal murder of Peyton Tuthill in 1999. accident. A three and a half foot long, Subsequent brain scans found decreased thirteen pound iron rod was blown into brain activity in Page’s ventral prefrontal his head, travelling behind his eye and out cortex. It was argued that a catalogue through the top of his skull, resulting in of childhood problems, including poor the loss of much left frontal lobe tissue. nutrition, parental neglect, physical and Gage survived the accident and his doctor sexual abuse and head injuries, together with documented his subsequent personality, a family history of mental illness, had left him cognitive and emotional changes. He was unable to control his behaviour. On the basis recorded as losing his inhibitions, behaving of his brain pathology, Page’s death sentence inappropriately and violently, even reportedly was reduced to life imprisonment. molesting his children. Phineas Gage, seen holding the tamping iron which passed through his skull. From the collection of Jack and Beverly Wilgus Donta Page Scans of Donta Page’s brain (left) and a normal The skull of brain. The images show decreased activity in Phineas Gage Page’s pre-frontal cortex. The orbitofrontal cortex (OFC) is involved in the regulation of social behaviour and, in one Frontal lobe damage infamous case, displacement of this structure in This damage typically lowers inhibitions or the right hemisphere by a brain tumour was linked emotional control, affecting the way we respond with an individual’s ‘acquired paedophilia’. After to triggers in the environmental. the tumour was surgically removed, behaviour However the frontal lobe is a complex structure returned to normal. A change in behaviour and can be divided into sub-regions. The indicated the tumour had regrown. When it was prefrontal cortex (PFC), for example, is important removed for a second time, behaviour once again in judgement, decision-making and impulse returned to normal. control (sometimes described as the ‘crowning achievement’ of the human brain, it is one of Limbic region damage the slowest brain regions to mature). If damage Damage to the amygdala and alterations to its occurs in childhood, problems developing an function have been linked to aggressive behaviour. understanding of moral behaviour can arise; in For example, epilepsy, localised to the amygdala, adulthood, this damage may be associated with an may be associated with episodes of aggression inability to control inappropriate behaviour. in some patients. Brain tumours affecting limbic Reduced activity of the PFC has been implicated system function have also been linked to aggressive in aggression and violence, as exemplified by the behaviour, and even to murder such as in the case case of Donta Page. of Charles Whitman. Catalyst February 2016 www.catalyststudent.org.uk 7 when we say that a given behaviour is genetically Charles Whitman influenced, this is not to say that it is inevitable or Charles Whitman was an engineering student ‘determined’. Predisposition is not predestination. at the University of Texas. In 1966 he killed 16 Second, when we say that genes influence criminal people, including his wife and mother. During behaviours, this does not mean that genetics can the post-mortem examination of his brain a explain why certain individuals commit crime. tumour was found near to the right amygdala, which some scientists think might have led to Whitman’s inability to control his emotions and actions. A doctor examines a CAT scan of a patient’s brain. Epigenetics is an exciting new development in our understanding of how the environment is involved in the expression of genes and linked to antisocial behaviours. The term is used to describe how environmental factors such as stress, diet and drugs can ‘switch on’ (express) and ‘switch off’ (silence) genes. Scientists are trying to understand how early life experiences can alter gene expression patterns in the developing brain, altering development and function of areas such as the hippocampus and Charles Whitman frontal lobes. It is possible that there will come a time when, as part of an offender’s defence, their legal team argues absence of parental interaction In studies of otherwise untreatable aggression, the and moral teaching has altered gene expression surgical removal of the amygdala on both sides of leading to frontal lobe impairment and an inability the brain is reported to have resulted in moderate to to control behaviour? excellent improvement of aggressive in about 75% of patients. There is even evidence to suggest that What can we conclude? amygdala dysfunction may also lead to poor fear conditioning which may predispose an individual Criminal behaviours and their causes are diverse, to crime. One study reported that a failure to form leading some philosophers and scientists to an association between a loud noise and fear at comment that it is unlikely we will ever find a brain the age of three years appeared to precede criminal ‘signature’. However, certain types of traumatic activity in adulthood. brain injury seem to increase the risk of offending behaviour and there is increasing evidence that Genes and behaviour: nature, brain tumours, epilepsy, levels of chemical nurture or both? neurotransmitters in the brain and many other biological factors can increase antisocial behaviour Many researchers over the years have reasoned that and criminality. criminality may be genetically determined, that Human behaviours are complex in their origins, there might be a gene or set of genes running in arising from an interaction of genes, environment, families and predisposing to deviant behaviour. developmental history, and the evolutionary Behaviours such as impulsivity, which is processes which have shaped brain structure and correlated with antisocial behaviour, appear to be function. In the years to come, we will inevitably heritable. However, the contribution of any single learn more about how these factors interact, gene to antisocial and aggressive behaviour is most influencing criminal behaviours, but at present likely to be very small, with several genetic variants we must be careful not to misinterpret our limited incrementally increasing the risk of antisocial findings and make generalisations about criminal behaviour. Genes interact with clusters of genes, behaviour without supporting evidence. which interact with networks of genes that in turn interact with the environment. Further, when Dr Guy Sutton is Director of Medical Biology Interactive and considering the relationship between genes and Honorary (Consultant) Assistant Professor at University of crime, two important points must be noted. First, Nottingham Medical School. 8 Catalyst February 2016 www.catalyststudent.org.uk.

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